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By Edward A. Barrett, Launa Mallett, Charles Vaught, Kathleen M. Kowalski, Michael J. Brnich, Lynn L. Rethi, Robert Randolph, William J. Wiehagen

The goal of the Pittsburgh Research Laboratory's training research is to explore the relationship between valid instruction and improved worker performance. Studies summarized in this paper include: (a) the development and assessment of training techniques that strengthen miners' ability to act competently in emergencies; (b) investigations of classroom simulations that enhance the perceptual, judgment and decision making skills of workers confronted with mine hazards; and (c) field studies of the linkages between financial investments in occupation at skills training and measurable outcomes.' The authors maintain that better ties between training and performance will aid long-term human resource development. The best way to establish this connection is through the use of objective and reliable data.

By R. V. Ramani, R. Stefanko, G. W. Luxbacher

Mine ventilation can be broadly defined as the branch of mining engineering primarily concerned with the controlled flow of air through mine airways to maintain an acceptable atmospheric environment wherever men work or travel underground. Martinson (1976) has defined three elements of mine ventilation, 1) an engineering element concerned with establishing quality control (removal of dust and gases), quantity control (regula¬tion of air direction and magnitude) and climatic conditioning (temperature-humidity control), 2) a biological element in which an understanding of biological response is used in assessing the mine environment, and 3) a philosophical element requiring judgements as to the degree of risk or worker discomfort that is socially acceptable. Most texts on ventilation, such as Hartman (1961), limit themselves to a discussion of the engineering element. Although also limiting his text to engineering control, Weeks (1928) thoughtfully addresses the other elements in the preface of his book where he states: "Life is brief and happiness elusive under the best of conditions; so beside the commercial aspect must be placed the humanitarian. Is it not reasonable that the operator should give his men a chance to spend their working hours in a comfortable environment, with the danger of sudden death or disability reduced as much as possible?" The statutory requirements of ventilation are, in most countries, established on the basis of biological response as determined by basic research or are dictated by social awareness, often touched off by major disasters, resulting in demands on regulatory bodies for more stringent requirements. To a limited extent, the philosophical and biological elements of ventilation are intertwined in that social awareness may

Jan 1, 1977

By David Hoadley, Kenneth R. Maser, Ashok B. Boghani, James E. Billar, D. Randolph Berry, Mackenzie Burnett, Robert H. Trent

A. 3 Program Description The computer program developed to simulate events in the case of fire in the mine is described in this section The description is divided into three parts. 1. Program Capabilities This part summarizes what inputs can be changed, what outputs can be obtained and demonstrates program flexibility through suggested uses.

Jan 1, 1976

By Kenneth E. Hjelmstad

The U.S. Bureau of Mines (USBM) has developed an electromagnetic (EM) fire warning alarm sys-tem for underground mines. The system generates a magnetic field for through-the-earth signal trans-mission to microreceivers carried by individual miners. EM fields can induce electric currents in metallic conductors; if an EM transmitting antenna and an electric blasting cap array are too close, the field could induce a current in the blasting array and cause an unintentional initiation of the electric detonators. The USBM conducted tests that define the safe and unsafe regions for using electric detonators near the transmitting antenna of the warning alarm system. The minimum safe distance between a transmitting antenna and a blasting array is the distance where the induced electrical current in the blasting array is 50 mA, which is the safe current level specified in Federal mine safety regulations. Tests indicate that at transmitting power levels of 100-and 1,000-W, separation distances of 9 and 21 m, respectively, were required. These distances are small compared with the dimensions of a mine. Thus, the tests indicate that, with proper placement of the transmitting antenna, the warning system can be used safely in the proximity of blasting arrays.

Jan 1, 2010

By David Hoadley, Kenneth R. Maser, Ashok B. Boghani, James E. Billar, D. Randolph Berry, Mackenzie Burnett, Robert H. Trent

A. 4 Illustrative Simulations The capabilities of the program are demonstrated by simulating various evacuation cases in different situations for a particular mine. The mine selected for the illustrative simulations is the mine I C' , as described in Section 2, chosen particularly because of availability of mine characteristic data and mine evacuation results for test drills. These evacuation results can be used to verify validity of the predictions made by the program A.4 1 Mine Characteristics A schematic diagram of the mine is shown in Figure 19. The figure shows all the major shafts, drifts, raises and stopes of the mine in the form of a network. There are four hoists, Hoist No. 1 and Hoist No. 2 are assumed to be single drum hoists and Hoists Nos. 3 and 4 form part of a double drum hoist, with Hoist No. 4 being the main hoist (master hoist) The positions of the 133 miners, typically working in a day shift of the mine, are also shown in the figure. The miners are identified by a miner number, and their total number on each level is chosen from the data on the fire drill simulated as Case No. 1 in the illustrative simulations.

Jan 1, 1976

By Joseph J. Wallace, Lloyd Williams, D. A. Reynolds, James J. Dowd, R. F. Abemethy

"SUMMARY AND CONCLUSIONS1. The investigation shows that the most important beds in Allegany County, from the standpoint of known recoverable reserves are: Lower Bakerstown, Upper Freeport, Upper Bakerstown, Upper Kittraing - less important beds are: Sewickley, Waynesburg, Pittsburgh, and Barton. 2. Known measured and indicated reserves in all beds, based on a minimum thickness of 14 inches and 1,800 tons per acre-foot of coal in place, are estimated to be 556 million short tons, as of January 1, 1951. Of this total, 304 million short tons is in beds 23 inches and more thick. Areas in each bed were omitted from the estimate because available data relative to the bed characteristics are too meager to permit making an estimate that conforms with the definitions of measured and indicated coal adopted for this study. Should future drilling or development prove reserves in these areas, such reserves should be added to the total eat ted reserves.3. Recoverable reserves of coal have been estimated in beds 28 inches and more thick. This thickness is about the minimum now being mined by hand-loading onto conveyors in the Appalachian region. The weighted average recovery for all beds in Allegany County, as determined by this investigation, is 49.8 percent. This percentage is based on the total thickness of coal (less partings 3/8 inch or more thick) in the bed rather than on the thickness of the coal mined. Based on the weighted average percent recovery for all beds in Allegany County, the recoverable reserves are estimated to be 152 million short tons as of January 1, 1951.4. The Allegany County coals are low-volatile bituminous in rank.5. The Allegany County coals are strongly coking."

May 1, 1953

By Lloyd A. Morley, Alan M. Christman

Introduction A wealth of information exists which deals with electrical grounding, both from a general viewpoint and from a specifically mine-oriented approach. Many parameters must be investigated in order to thoroughly cover all of the variables which govern the performance of electrical grounding systems. The emphasis of this work on open-pit practices re- presents a new development in the field of grounding research, and an exhaustive review of the relevant historical documentation is especially desirable. Grounding System Purposes What purposes are served by a grounding system? The answer is four-fold and may be summarized as follows. First, it must limit potential gradients between conducting materials in a given area (56). When a phase conductor comes into contact with a machine frame, current flows through the equipment, which tends to become elevated above ground by an amount equal to the voltage on the conductor. If a man were to touch the machine while he was simultaneously connected to ground in some manner, his body would also tend to become elevated in potential, possibly to a lethal extent. Thus, the grounding system should provide a low- resistance path for the fault current to return to the source. The maxi- mum potential to which a man could be exposed when touching a machine frame is equal to the voltage drop along the ground conductors inside the power cable, as shown in Figure 1 (54). The ground conductors, therefore, (page # 96 is missing from the original document)

Jan 1, 1976

Establish a procedure for reliably determining cation exchange parameters at an in situ mining site. The Problem Predicting the movement rates of pollutants from waste disposal sites requires reliable measurements of cation exchange parameters since cation exchange can retard pollutant movement. Reliable measurements of these parameters are also required for predicting the length of time needed to restore groundwater quality after in situ mining. Cation exchange is otten the controlling mechanism for the replacement of leach solution cations by the cations in the returning ground-water. Unfortunately, laboratory measurements using core samples are of minimal reliability. The uneven clay distribution at most sites produces a high variability in laboratory results. In addition the flow pattern in the laboratory tests is different from that in the field. Approach Bureau of Mines research has developed a field-test procedure that is quick and yields reliable and representative data. A corresponding data analysis procedure was also established in order to verify the' applicability of the computer simulation model of cation exchange used in the analysis, and of the general analysis procedure, with actual field data.

Jan 1, 1986

By R. V. Ramani, A. S. C. Owili-eger

The rapid depletion of shallower coal reserves dictate that mining in the future will be deeper and more complex with more difficult natural conditions. Consequently, an increase in methane emission is expected. It is becoming evident that more accurate predictions and better planning are necessary to design efficient methane drainage systems. This objective can be achieved by the utilization of the knowledge of the physics of gas flow through coal seams and rock strata and by the application of digital computers in the solution of methane flow problems. Although the methane emission models described here have not been adequately applied to existing field operations, good agreement between actual field measurements reported in literature and the simulation results indicates the potential of these models for initial flow quantity approximations and ventilation planning. This report has, therefore, introduced to the mine operator yet another application of computers as a planning tool. AREAS FOR FURTHER RESEARCH The study reported here is by no means complete. Extensive research efforts should be directed to the following areas: (a) Better understanding of the physics of gas flow through porous media which exhibit fracture permeability. (b) Determination of field parameters which control gas migration. (c) Investigation of the effects of the rate of penetration on the emission rate and fracture propagation.

Jan 1, 1974

By H. Carroll

An ozone detector was built and evaluated for its applicability in smog-chamber studies. The detection method is based on the reaction of ozone with ethylene and the measurement of resultant chemiluminescence. In the first phase of evaluation, the detector's response to ozone was studied as a function of several instrument parameters, and optimum conditions were defined for the maximum and most stable responses to ozone. In subsequent evaluations, the method was checked for sensitivity, precision, and interferences and was compared with two alternative methods. Results showed the chemiluminescence method to be acceptably sensitive and precise for smog-chamber studies and superior to the Mast ozone meter and KI (colorimetric 1 percent neutral-potassium iodide method) methods in that it is specific for ozone.

Jan 1, 1972

By S. H. Katz, J. J. Bloomfield

In studies of mine and tunnel ventilation conducted by engineers of the Bureau of Mines , various smokes are used to determine flow of air , direction of the currents , and the rate of mixing . The instrument for generating streams of sulphur trioxide (SO ) smoke , shown in the drawing herewith, has been found helpful , convenient and practicable for such purposes ; it is also especially useful in some places where fire for generating smokes is not permissible . The apparatus consists simply of a glass tube containing fuming sulphuric acid on granular pumice stone , attached to a rubber syringe bulb . When a squeeze of the bulb blows air through the tube , a stream of dense white smoke evolves, which follows and makes visible the air currents . The tubes after preparation are hermetically sealed to prevent deterioration . When ready for use , they are easily broken open at a file scratch for the purpose on both tips , and inserted into a rubber nipple at the bulb . Sometimes it is of advantage to attach them to a longer rubber tube leading to the bulb . Tubes of the size shown (about 1/2 inch outside diameter by 5 inches long) are usually sufficient for the needs of a day . Thereafter they cease to fume because the acid absorbs moisture from the air and looses its effectiveness . Smaller sizes of tubes and larger have been made , but the size shown has proved most practicable . Immediately after a person has finished using a tube it should be buried or disposed of in a place where it will not be touched by shoes or clothing, or come in contact with wooden floors , furniture , or metals , because the acid , which will eventually leak from the tubes , is highly corrosive . -- Reports of Investigations , Department of the Interior , Bureau of Mines .

Jul 1, 1923

By J. Hanslovan, R. H. King

An investigation of the feasibility of shielding low-voltage trailing cables in underground coal mines is described. Both laboratory and under¬ground installation results are presented. The main objective of shielding is to reduce the electrical shock hazard; however, several problems will be encountered by mine operators who install shielded cables. Parameters related to such items as purchasing, splicing, troubleshooting, safety, and reliability are discussed. Some of these problems can be minimized by changes in cable constructions and shuttle-car reeling-device components. Both SH-C and SH-D constructions are considered.

Jan 1, 1979

By Joseph Cervik

Gas occurs in coalbeds in an adsorbed and a free gas state, Adsorbed gas is stored in the micropore structure and its transport is governed by Fick's law. The free gas occurs in the. fracture system and flows according to Darcy's law. These two modes of mass transport are interdependent. Production decline curves of coal-gas wells are of the constant percentage decline type and, thus, show no indications of flow characteristics peculiar to coal-gas reservoirs. The effectiveness of surface boreholes as a degasification scheme depends upon both good fracture permeability and a high fracture density. Conventional methods of reservoir engineering analysis are not applicable to coalbeds.

Jan 1, 1969

By David Hoadley, Kenneth R. Maser, Ashok B. Boghani, James E. Billar, D. Randolph Berry, Mackenzie Burnett, Robert H. Trent

5. General Escapeway Requirements 5.1 Escape Routes Present escapeway regulations state "Every mine shall have two separate properly maintained escapeways to the surface which are so positioned that damage to one shall not lessen the effectiveness of the other, or a method of refuge shall be provided when only one opening to the surface is possible." "Escape routes shall be a. Inspected at regular intervals and maintained in safe, travellable condition, b. Marked with conspicuous and easily read direction signs that clearly indicate the ways of escape." "Application. "Regular" intervals means at intervals no greater than monthly where conditions are stable and oftener where conditions may change." "Designated escapeways inclined more than 30* from the horizontal shall be equipped with stairways, ladders, cleated walkways, or emergency hoisting facilities." As can be noted in present and proposed regulations there must be two separate properly maintained escapeways. In most operations, the escapeways will consist of one route that is the normal travelway used in day to day operations. The second route is usually a return airway through old work areas. Based on this generally accepted practice, we will designate the two types as primary and secondary.

Jan 1, 1976

By O. M. Bishop

The Douglas fluorite property is in the Empire district of eastern Pope County, Ill., which lies near the west boundary of the productive Southern Illinois fluorspar field in Hardin and Pope Countios. Production from mines on the Douglas property accounts for about one-half of the 72,000 tons of fluorspar with which the Empire district is credited. This output was from the Sycamore, Pierce, Slapout, and Empire veins, which are normal fissure veins of little displacement along which there has been local wall-rock replacement by fluorite.

Jan 1, 1949

By L. C. IlsLey

"According to accident statistics, issued from time to time by the Department of the Interior, Bureau of Mines covering fatalities in coal mines, between the years 1870 and 1921 there were 4,897 deaths caused by explosives. The legislatures and safety commissions of the various mining States have Elected and formulated many excellent regulations in regard to the handling and use of explosives in an endeavor to keep this class of accidents as low as possible. An analysis or comparison of the explosive, regulations issued by over thirty States would make a very long paper, however, by subdividing according to phases and issuing several papers it is believed that the material will be more readily available. The first phase was treated in Serial No. 2405 of the Bureau of Mines (""State and Federal Electrical Shot-Firing Regulations,"" issued in October 1922) which gave a compilation of such regulations as apply strictly to electric shot-firing. The second phase under consideration is ""Who may set off blasts in coal mines.""In some States, the person who does the firing must be an ""authorized shotfirer,"" while in other States he must have proved his ability to do this work, and again in other States he is ""any person."" The present paper covers rules and regulations relating to this phase of shotfiring, and those States having similar regulations have been grouped as follows."

Jun 1, 1923

The Ringelmann Smoke Chart fulfills an important need in smoke abatement work and in certain problems in the combustion of fuels. A knowledge of its history and method of preparation is, therefore, of interest to many. Since instructions on its use are not shown on the recent edition of the chart, those included in this revision of the previous Bureau of Mines publication now are a necessary complement to the chart. More detail regarding the use of the chart is included than was given in the earlier version.

By Joseph C. Zelanko, Anthony T. Iannacchione

One of the most difficult and longstanding engineering problems associated with coal mining is the catastrophic failure phenomenon known as coal mine bursts (known in the United States as bumps). For more than 70 years, researchers and practitioners have attempted to determine whether this destruction observed underground is caused by stress conditions within the coal pillar or from distant seismic sources in the mine roof and floor strata. The role of confinement and the extent of failure in solid pillars and panels have also proven difficult to define. These are important issues, since control solutions need to be based on a fundamental understanding of the problem. Obsenations by U.S. Bureau of Mines researchers over the last decade have helped to clarify certain aspects of these issues. Microseismic sensors and geomechanic field measurements have located areas of excess energy release, identified stress conditions in coalbeds close to failure, and recorded the response of mine structures prone to bursts. In the present study, data available for a range of U.S. bursts were considered in an effort to evaluate both common and distinctive features. Although the attempt revealed little commonality, encouraging results were produced by categorizing coal bursts by source mechanisms. When a coal burst is thus categorized, differences in environmental factors-such as geology, stress fields, and mining methods-are highlighted, and viable control strategies are readily recognized.

By W. W. Adams, E. E. Getzin, T. D. Lawrence

"The thirteenth annual accident-prevention competition conducted by the Bureau of Mines during the calendar year 1937 was completed with 318 mines and quarries participating. This contest, known as the National Safety Competition, is open to all minas and, quarries employing 25 or more men underground or in the quarry or open pit. The entries are divided into five groups to obtain as nearly as possible uniformity of operating conditions and hazards. The five divisions are: (1) Underground anthracite mines, (2) underground bituminous-coal mines, (3) underground metal mines, (4) underground nonmetal mines, (5) quarries and open-pit mines. A bronze trophy, known as Sentinels of Safety, provided by the Explosives Engineer magazine, is awarded to the winner of each group. The trophy is kept by the winning company 1 year and then transferred to the winner of the succeeding year's contest. Certificates of Honorable Mention are given to plants ranking second, third, fourth, and fifth in each group and to all plants operating without a lost-time accident provided the period of exposure to hazard was not less than 30,000 man-hours. Relative standing in the contest is determined by the contestant's accident-severity rate, which represents the total number of days of employee disability from accidents per thousand man-hours worked by all employees.The 1937 contest was outstanding in that the accident-frequency rate for the contest group as a, whole was the lowest on record. Moreover, with one exception 1934, the accident-severity rate was the lowest ever attained: For frequency, 3S.0 accidents per million man-hours worked; and for severity, 8.2 days lost from accidents per thousand man-hours worked. The rates represent a decline of 62 percent in accident frequency since 1925, the first year of the contest, a remarkable accomplishment both for the contest group and for the purpose of the contest because a majority of the contestants have not only participated during the past year but have been enrolled several years, some enrollments even dating back to 1925."

Aug 1, 1938

By Clyde M. Pearce

The Lake Superior iron-mining district includes parts of the States of Michigan, Minnesota, and Wisconsin. The laws of each State provide for an industrial commission and for inspection of mines. The following extract from the General Orders on Mines, effective October 25, 1937, issued by the Industrial Commission of Wisconsin, is the only reference to the use of safety catches on mine cages or skips found in the laws and regulations in the Lake Superior iron-mining district: Order 316 - Cages for Hoisting Men. (c) Sides, Gates, and Safety Catches. ***Every cage shall be provided with safety catches of sufficient strength to hold the cage with its maximum load at any point in the event the hoisting cable should break. (d) Testing Safety Catches. The safety catches of cages and skips used to hoist men shall be kept well oiled and in good working order. They shall be tested at least once each month by tying up the cage or skip with hemp rope, lowering a few feet of hoisting cable on top of cage, then cutting the hemp rope, provided that any other system of testing, which is equally effective, may be used.

Jan 1, 1945